why don't I see more sites using Amazon logins? I almost always see Google, Twitter and FB only. It could be that Google, Twitter, and Facebook are truly inter

why don't I see more sites using Amazon logins? I almost always see Google, Twitter and FB only. It could be that Google, Twitter, and Facebook are truly international, while Amazon is not available in many countries. Unless your app is US or UK centered, you'd be missing out on quite a big population. EDIT: the list of Amazon countries appears to be United States, the United Kingdom and Ireland, France, Canada, Germany, Italy, Spain, Netherlands, Australia, Brazil, Japan, China, India, and Mexico.